The present invention relates to a pneumatic tire, more particularly to an asymmetrical tread pattern capable of improving noise performance without sacrificing wet performance and steering stability.
In general, pneumatic tires for example passenger tires are provided in the tread portion with tread grooves such as circumferential grooves and axial grooves.
If tread grooves are increased in the volume in order to improve wet performance of the tire, there is a problem such that the rigidity of the tread portion is decreased and the steering stability is deteriorated. Further, air tube resonance becomes liable to occurs when the groove volume is increased, therefore there is a problem such that noise performance is deteriorated. Thus, the wet performance is contradictory to the noise performance and steering stability.
In order to solve such contradictory problem, Japanese Patent Application Publication No. 2003-285610 discloses a pneumatic tire in which a circumferentially continuously extending rib is formed on each side of a circumferential groove to isolate the circumferential groove.
In such a pneumatic tire, however, there is room for simultaneous improvement in the steering stability, wet performance and noise performance.